Vacuum tube



Oct. 29, 1946.

'Filed DeC. 15, 1942 A A ww m1 ww I f/ QN. wb www, Mw www H mw B ma VL mE u. m Q ww.- n QN. ww. QN,

Patented Oct. 29, i946 VACUUM TUBE Emile Labin, New York, N. Y., assignor` to Federal Telephone and Radio Corporation, Newark, N. J., a corporation of Delaware` Application December 15, 1942, Serial No. 469,0 55' 16 Claims. (Cl. Z50-27.5)

This invention relates to improvements in vacuumv tubes, and more particularly to vacuum tubes of the cavity type, adapted for use at high frequencies.

An object of this invention is to provide a novelv improved design for a cavity tube.

Another object of this invention is to provide a high frequency cavity tube, capable of handling high power thermionic emission currents.

Still another object of this invention is 'to pro- Vide a high frequency cavity tube, having large heatndissipating surfaces integral'with the electrode elements.

A further object of this invention is to provide a Vacuum tube in which the electrodes are formed as integral extensions about the periphery of a resonant cavity, and cooperate with other walls of the cavity in constituting the perimeter.

In general, the invention relates to a cavity tube in which the tube electrodes are built about the cavity resonator, in contrast'to usual types of cavity tubes in which the resonator is built about the tube electrodes.

Other objects and advantages of the present. invention will appear from the following description of a preferred embodiment and a modification of my novel tube, illustrated in the accompanying drawing, in which:

Fig. 1 is a vertical cross-sectional View of a preferred form of tube construction; and

Fig. 2 is a partial cross-sectional View illus- Atrating a modified structural detail.

While various'forms of cavity tubes have been heretofore proposed, all of such known tubes are so designed that the resonator structure is built about the tube elements; in other Words, the idea has been t start with a vacuum tube and add the necessary resonator structure to it. This conception of building a cavity tube has resulted in structural limitations, both with respect to the tube elements and with respect to the resonator structure, which seriously interferes with the application of such types of tubes to ultra-high frequency work. The present invention is a radical departure from previously proposed constructions in that I have made the resonant cavity the central part of the tube and have built the tube elements about the cavity. This arrangement provides greater freedom and choice in design and permits the use of the optimum thermionic and electronic relationships- In Fig. 1 of the attached drawing, there is illustrated an example of a type of cavity tube formed in accordance with the present invention,

'through the seal 30, outside of the tube.

2y Two equally dimensioned circular metal plates I0 and I2 are spaced apart parallel to one another by suitable means` such as quartz spacing insulators I4, which also provide the cavity with the necessary strength to withstand atmospheric pressurewhen the resonator is evacuated. The insulators I4arepreferably. located along the locus of voltage minimum points, which can` be previously determined. Inthe form of invention illustrated, the upperplate I0 is .providedlwith a thin ring-shaped metall member I6, attached to the plate and having its outer periphery extending ysubstantially labout the *outerA periphery of the plate. The lovverplatevIZl is provided with an upstan'ding ringk I8, rigidlyattached thereto with'its outer periphery at about the periphery of theV lower plate; A suitable annular grid structure 2B Vis attached to the upper edge of the ring, I8, so that it is radially spaced from theI pe ripheryfof the ring I6,y by adesired amount. The plates lil and I2 andtheinner surfacev of the ringsrl and I8 form the resonant cavity for the vacuum'tube. About the A.grid 20 is Apositioneda ringeshaped cathode 22, which may be indirectly heated as by heater coils-24. The cathode 22 is provided with a radial extension 26 whichY maybe supportedby' the spacers I4 for positioning'the cathoderelatively'to.the grid.A A-thin disk 28, open at Vits' center is also positioned about the 'grid 20. and is spaced a short distance from the r'adialiextension 26 on the cathode, the extension 26and the disk 28' forming between thema ca.- pacitative'coupling. The electrodes `and theV resonant vcavity may bev enclosed by a suitable glass 'seal 3l),` connected at one end to theangular knife edge 32, attached'tothe top'of the plate I0, and

on the other hand to the annular knife edge. 34 attached to the'bottom of the plate I2. The disk 28 'is preferably of such diameter that it exteilds e heating coil supporting leads 35 will also extend through seal 30 at 3l. On the bottom of-the plate I2"is provided an annular 'rim 36, while the under side of the disk 28 outside of the tube periphery is also provided wtha depending annular rim 38. An open toroid wis setto slidably engage the depending portions of the rims 36 and 38. The toroid tilithus forms aivsecond external cavity coupling` ythe grid 2U, through"A the lower plate I2, to the cathode 24 through the disk 28 capacitatively coupled with the radial extension 26. By slidingthe toroid 43 on the depending rims, the size of the .external resonant cavity can be Varied as desired YCoupling to the second resinto the same through a suitable opening in the` upper plate IIl. For this purpose, the. upper surface of the plate I Il may be provided with a threaded bushing 50, positioned about the opening, the bushing supporting in 'turn a" threaded L collar 52. The collar 52 slides in an annular groove formed in the extension 53 of a ilexible bellows 56, positioned about the opening. A glass seal 54 is connected about a knife edge on the extension 5,3 and supports the rod 48. It will be obvious that rotation of the collar 52 of the bushing 50 moves the rod 48 in and out of the cavity,

to a limited extent, while the flexible bellows 56 maintains an air-tight fit. The upper surface of the plate III may also be provided with an upstanding ring 578 supporting a metal cylinder 60, which may serve as a plate line.

A second arrangementwhich is in most respects similar to that illustrated Ain Fig.'l is shown'in Fig. .2. In thiscase, however, the electrode surparatus, is therefore, made only by way of example and not as a limitation on the scope of my invention as set forth in the objects and the ac.d companying claims.

What I claim is:

1. A cavity resonator electron tube including apair of spaced-apart metal plates, each point on'. one plate being at substantially the same distance: from the corresponding point on the other plate,l

as measured along a line normal to the surfacet at; these points, an anode electrode electrically' connected to and positioned about the periphery' of one of said plates, a second electrode connected .to and positioned about the periphery of the other facesare mounted parallel to the plates instead of at right angles thereto.l The ring IIB depending from within the plate III isv provided with a radialjrim, serving as the active anode surface, whileja grid I20-is supported at the upper end of the ring I I 8, so that it is parallel to the radial rim of the; anode. The cathode 122 maybe conart.` For example, while the plates I0 and I2 have been illustrated as Vsubstantially circular, and

while `such a coniiguration, having no sharp corners is generally to be preferred, the invention is applicable for use in connection with plates of any desired shape. While the plates have been shown as ilat, they also could be curved, provided that in any event each point on one plate is at the same distance from the corresponding point on the other plate as measured along a line normal to the surface vat these points. While the tube has been illustrated as of the triode type, it is also contemplated that one 'of the depending rims forming the outer peripheryof the resonant cavity could be used as a cathode electrode, in which Vcase 'the tube could-be a diode. The principles of the invention are, therefore, equally applicable to diodes as well as triodes. Other modifications, particularly rin details of construction, will be fairlyobvious to those skilled in the art and it is contemplated that such modifications form part of the present invention provided that in all cases,

the.principle of constructing the vacuum'tube elementsv about the periphery of'a cavity'resonaf tor is retained. The description ci specic apstructed similarly as in Fig. l, but in this case it plate and spaced from the anode, said electrodes and said plates forming the perimeter of a cavity resonator, and sealing means enclosing said electrodes, closing the space between the two plates. 2. The combination according to claim l, in

which said second electrode is a grid, in combinae tion with a cathode electrode positioned exteriorly of and on that side of the grid opposite the anode.

3. The combination'according to claim 1, in which said plates are at parallel plates and said electrodes are formed as oppositely inwardly directed rings extended about the peripheral edges of said plates.

4. A cavity resonator electron tube including, a pair of spaced-apart at parallel plates forming part of the perimeter of the tube, an anode electrode electrically connected to and positioned about the peripheral edge of one of said plates, a grid electrode connected to and positioned about the peripheral edge of the other plate and spaced from the anode, said plates and said electrodes forming the perimeter of a cavity resonator, a cathode electrode positioned on that side of the grid opposite the anode, and sealing means enclosing said electrodes between the plates.

5. The combination according to claim 4, in which said plates are circular and said anode and grid electrodes are formed as rings inwardly directed toward one another.

6. A cavity resonator electron tube comprising, a pair of at circular metal plates, insulating Aspacing means between said plates positioning them parallel with one another, a thin metal ring connected to the periphery of one of said plates forming .anode electrode, a second thin metal ring connected to the periphery of the other plate, an annular grid supported by the second vmetal ring having a lateral face parallel to and spaced from said extension, said ring extending through and supported by said sealing means, and forming a terminal capacitatively coupled with said cathode.

8;'The combination according to claim 6, in which said cathode has an outwardly directed radial extension, in combination with a thin metal ring having a lateral face parallel to and spaced from said extension, said ring extending through and supported by said sealing means, and forming a terminal capacitatively coupled with said cathode, and means outside of said cavity resonator and outside of said sealing means,

forming a second cavity resonator between the grid-supporting plate and said parallel metal ring.

9. The combination according to claim 6, in which said cathode has an outwardly directed radial extension, in combination with a thin metal ring having a lateral face parallel to and spaced from said extension, Said ring extending through and supported by said sealing means, and forming a terminal capacitatively coupled with said cathode, a rim depending from said parallel ring outside of said sealing means, a second rim depending from the outer surface of the gridsupporting plate in the same direction as the iirst rim, and a toroid having an open lateral face engaging the two dependent rims, and forming with them a second and external cavity resonator coupling the grid to the cathode through said capacitating coupling.

10. The combination according to claim 6, in which the grid-supporting plate has a substantially central hollow opening, in combination with a flexible diaphragm covering this opening and sealed at its edges to the plate, means operatively connected with said diaphragm for moving it to tune the resonator, and resonator coupling means supported by and extending through the other plate.

11. The combination according to claim 6, in which said cathode has an outwardly directed radial extension, in combination with a thin metal ring having a lateral face parallel to and spaced from said extension, said ring extending through and supported by said sealing means forming terminal capacitatively coupled with said cathode, a rim depending from said parallel ring outside of said sealing means, a second rim depending from the outer surface of the grid-supporting plate in the same direction as the rst rim, and a toroid having an open lateral face adjustably, slidably, engaging the two depending rims, and forming with them a second and eX- ternal cavity resonator coupling the grid to the cathode through said capacitative coupling.

12. The combination according to claim 6, in which said rings are both mounted at right angles, to and between the metal plates, in which said grid surrounds the rst metal ring, and in which said cathode surrounds the grid.

13. The combination according to claim 6, in which the rst metal ring is inwardly directed t0- ward the other plate and is provided at its outer end with an outward radial extension intermediate and substantially parallel to the two plates, in whchsaid second metal ring is inwardly directed toward the other plate, and in which said grid is connected to the outer end of said second ring and extends radially parallel to the radial extension on the rst ring.

14. A cavity resonator tube comprising in combination, a pair of at circular metal plates, insulating spacing means between said plates positioning them parallel with one another, a thin metal ring connected about the periphery of one of said plates, inwardly directed toward the other plate and provided at its outer end with an outward radial extension intermediate and substantially parallel to the two plates to form an anode electrode, a second thin metal ring connected about the periphery of the other plate, inwardly directed toward the iirst plate, said plates and said rings dening the perimeters of a cavity resonator, a grid connecting to the other end of said second ring and extending radially, parallel to the radial extension on the first ring, an annular cathode mounted about the side of the ring opposite the anode, said cathode being formed with an outwardly directed radial extension, sealing means enclosing said electrodes and connected between the two plates, a thin metal ring having a lateral face parallel to and spaced from said extension, said last ring extending through and supported by said sealing means to form a terminal capacitatively coupled with said cathode, and means outside of said cavity resonator and outside of said sealing means forming a second cavity resonator between the grid-supporting plate and said parallel metal ring.

15. The combination according to claim 14, in which said second cavity resonator forming means comprising a rim depending from said parallel rim outside of said sealing means, a second rim depending from the outer surface of the grid supporting plate in the same direction as the firstK rim, and a toroid having an open lateral face engaging the two depending rims.

16. A cavity resonator electron tube including, a pair of spaced-apart metal plates, a pair of spaced electrodes respectively mounted on and about the outer periphery of said plates to form with said plates the perimeter of a cavity resonator, and sealing means connected between said plates and enclosing said electrodes.

EMILE LABIN. 

